5-aminosalicylic acid inhibits colitis-associated colorectal dysplasias in the mouse model of azoxymethane/dextran sulfate sodium-induced colitis.
Clapper, Margie L. PhD 1,*; Gary, Monique A. MS 1; Coudry, Renata A. MD, PhD 1; Litwin, Samuel PhD 1; Chang, Wen-Chi L. PhD 1; Devarajan, Karthik PhD 1; Lubet, Ronald A. PhD 2; Cooper, Harry S. MD 3
Inflammatory Bowel Diseases.
14(10):1341-1347, October 2008.
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Background: The impact of the antiinflammatory agent 5-aminosalicylic acid (5-ASA) on the risk for colitis-associated colorectal cancer remains controversial. The chemopreventive activity of 5-ASA was evaluated in the Swiss Webster model of azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced colitis-associated neoplasia.
Methods: Mice were injected with AOM (7.4 mg/kg i.p.) and randomized to receive either vehicle or 5-ASA (75, 150, and 225 mg/kg) for the remainder of the study. DSS treatment began at 9 weeks of age and continued for 3 cycles. At the time of sacrifice (18 weeks of age), the entire colon and rectum were processed for histopathologic examination.
Results: An inverse trend was observed between dose and multiplicity of colonic dysplasias in all drug-treated groups (P = 0.03), with animals receiving 75 mg/kg 5-ASA exhibiting 56% of the number of dysplasias of the AOM/DSS controls (mean /- SEM: 7.6 /- 1.4 and 13.6 /- 2.7, respectively). Administration of 75 mg/kg 5-ASA decreased both the mean multiplicity of flat dysplasias (1.8 /- 0.4 for drug-treated versus 5.6 /- 1.2 for AOM/DSS control) and the burden of polypoid dysplasias (tumor burden: 6.7 /- 2.7 for drug-treated versus 14.9 /- 3.9 units for AOM/DSS controls) significantly (P = 0.002 and 0.04, respectively). Inflammation was least severe in the 75 mg/kg group, which exhibited the fewest number of colorectal tumors.
Conclusions: These data suggest that low-dose 5-ASA may be efficacious in preventing colitis-associated dysplasias and provide strong support for optimizing this therapy for the prevention of colonic neoplasms in patients with ulcerative colitis.
(C) Crohn's & Colitis Foundation of America, Inc.